Learning Curve
by bravevulnerability
Summary: She really hates her training officer. Three shot. AU.
1. Chapter 1

**A/N: Inspired by the Kate Beckett kickboxing scene in 8x03, PhDead. Completely AU.**

* * *

Her knuckles ache, her muscles burn, and her eyes sting from the sweat, but her determination to improve is stronger than the pains lacing through her body and bones.

"Need a partner?"

Beckett rolls her eyes and lands another high kick to the punching bag dangling in front of her, stumbling a little when the bag swings and her leg threatens to go with it.

"I could at least steady the bag for you, Beckett," Officer Castle quips, strolling towards the mat she's occupying. "Or we could do some one on one training if you'd prefer."

She hates her training officer. Of course he knows her tragic backstory, anyone with a file on her does, and while she appreciates the lack of acknowledgment to the true reason for enrolling in the Police Academy and graduating into the final leg of her training to become a homicide detective, she still doesn't like him.

He's smug and charming and too good to be a cop, too happy and carefree, and yeah, maybe it's a little ridiculous to despise him for having a pleasant attitude, but after embracing the hurt, the anger, and the numbness for so long, she doesn't exactly do well around the joyful.

"Don't you have something better to do?" she mutters, flexing her fingers, wincing at the splinters of soreness rippling from her knuckles.

"I'm your training officer," he reminds her, as if she's managed to forget. "It's kind of my job to train you, so..."

"Then train me," Beckett spats, her hands falling to her sides in exasperation, but Rick Castle merely smirks at her and comes closer.

"Let's start with your form," Castle begins standing opposite her with his hands raised in a block. "Try to sidekick me."

"Gladly."

Kate takes a breath and balances on her left foot, grits her teeth and extends her right leg into a swift kick that should land a blow to his throat, but Castle catches her ankle, spins her away, and sends her crashing to her knees.

"Too low and too fast, left you unsteady. I shouldn't have been able to knock you down like that."

Beckett growls under her breath but gets back to her feet, positions herself for another try.

"Tighten your core," Castle instructs, preparing for her next strike. "Focus on where you want the kick to land."

She grunts with the next kick, grazes his sternum before Castle snags her ankle again, but he doesn't throw her away this time, holding her there.

"Find your balance."

"Let go of my leg," she huffs, on the verge of tipping over, but Castle doesn't release her and she shoots him her worst glare as she steadies herself, ensuring she'll no longer sway on her single limb.

Officer Castle lifts her leg higher, so the sole of her foot is positioned at the base of his throat. The stretch of her muscles burns with the extension, but it's good. So is the heat of his skin against hers.

"Feel the difference?" he asks, quirking his brow at her and lowering her leg, releasing her.

"Yeah," she breathes, reeling her leg back in and bouncing on the balls of her feet to eradicate the sudden tension zipping through her veins. "Let's go again."

* * *

Kate sweeps her leg between his, tangles their feet and sends him down on his back, but Castle manages to hook his heel in the back of her knee, bringing her down on top of him.

A gasp of surprise rushes past her lips as they collapse together, his laughter rumbling beneath her chest, hearty and infectious. They've been sparring for the last hour and the ache in her body has gone numb with the promise to return in the morning in the form of stiff muscles and aching joints, but she doesn't care. She finally took down her training officer after being the one on her back for the last sixty minutes.

"You're a quick learner," Castle pants and she notices he's grinning when she lifts her head from where it landed on his shoulder through their fall.

"Well, you aren't the worst teacher," she muses, using the hands on either side of his head to elevate herself into a hover above him.

Her hair is slipping free from the ponytail she managed to rope it into, the stray strands falling around her face, clinging to the damp, heated skin, and something about her above him, practically on top of him, with her hair threatening to unfurl in a curtain around them has his pupils dilating, the bright cerulean of his eyes darkening to a fierce cobalt that has an entirely different kind of burn spilling through her body.

But before she can even consider doing anything about it, Castle is curling his arm under one of her knees, flipping them over so quickly that the breath is knocked right out of her.

"Never let your guard down, Officer Beckett," he murmurs, staring down at her with one of his eyebrows arched and half of his body draped atop hers.

"Noted," she grits out, resisting the ridiculous urge to use her unrestrained leg to twine with the other around his torso and hold him still while her body arcs into the enticing wall of his.

"I'm going to hit the showers, I'll see you bright and early tomorrow?" Castle inquires, untangling his arm from her leg, rising on his knees and scraping a hand through his sweat dampened hair.

"Tomorrow," she confirms, remaining flat on her back on the mat with her chest heaving and her eyes closed, listening to him walk away and waiting until the shower has cut on to force herself up and to her locker.

She still hates him, she does, this is just... physical attraction. Totally normal, completely manageable, and definitely not an obstacle that will get in the way of her true goal for being here.

Justice for Johanna Beckett. Nothing else matters.

She has room for nothing else.

* * *

Training in the precinct gym with Castle is not the only form of teaching she receives from him, but it's unquestionably become her favorite. Sure, working with him and her fellow trainees on the firing range or roleplaying situations they could face out in the field is always informative, but this - the physical intensity, the burn that reverberates from her lungs to the rest of her body, the contact with her training officer - provides her with a form of tangible knowledge and a release she's grown to crave.

They're nearing the end of their daily session today and she has his head in a lock between her thighs.

"Okay, now use the momentum of the roll to flip me."

Kate exhales before following his instruction, tightening her inner thigh muscles and rotating them the necessary 180 degrees until she is no longer on her back and his is flat on the mat. Castle attempts to reverse the move, hook a leg around her calf to bring her tumbling forward, but Kate plants her knees firmly in the mat, pins him beneath her in a maneuver that has him groaning.

"Submit," she growls, jerking his arm in a twist he taught her last week, squeezing the knees bracketing his ribcage.

Rick slaps his free hand to the mat and Kate releases him, lets him flop back down, panting and breathless.

"Has the student become the teacher?" she teases, still attempting to catch her own breath, dropping forward to rest her hands on the worn surface of the mat beside his head, hovering above him once again. It's not exactly an odd position considering their activity, but Castle always notices the shift, that her stake of dominance holds a hint of something more.

"You're younger than me, the extra stamina gives you an advantage," he counters, his leg twitching, and Kate sinks down, drapes her body over his before he can even think about trying to regain the upper hand.

"Sore loser," she hums. "Does this mean going all night is out of the question for you?"

Castle chokes on a laugh, but smothers his smile quickly, leveling her with a reprimanding look instead.

"You'd be surprised what a man of my age can do," he informs her and oh, that sounds like a challenge, one she so badly wants to accept.

"Oh yeah?" Beckett returns, shifting above him, rolling her hips ever so slightly. "Surprise me."

Castle startles beneath her at the movement, as if being snapped from a haze, and immediately begins reaching for her hips, ready to remove her.

"Officer Beckett-"

No, no professional bullshit. Not now.

Kate grinds down, her hips clashing with his, and his hands grip her harder, bruising as he goes still.

"Kate," he breathes, eyes screwing shut. "We can't."

Indignation flares hot in her chest, but it's too late. Her body is already wound taut with tension that has existed from the day they started these private training sessions, from the day she met this infuriating man and felt the devastating attraction burn through her grief, and she can't stop now. She won't.

Especially not if he wants her back.

"Why?" she challenges, lowering her cheek to press to his, the breath of her question washing over his ear.

"You know why."

"A stickler for the rules all of the sudden?" she mumbles, tightening her knees at his waist, circling her hips once more, and feeling the groan building in his chest.

"I'm not a good person to be involved with," he tries to reason with her through gritted teeth, the hands at her waist loosening. "Not in a good place to be involved with anyone either."

"Neither am I, but I'm not asking you to be my boyfriend, Castle," she states, withdrawing just far enough to see his face, to stare down into the murky pools of arousal bleeding from his blown pupils, overtaking his irises.

"Then what is it you're asking for, Kate?" he murmurs, those wary hands gliding from her hips to the small of her back, grazing the skin above the elastic waistband of her pants, left unprotected by the tank top that has ridden up her spine.

"To feel something." Her hips rock hard into him, her lower body grinding with intent to prove her point, to feel the heat simmer in her abdomen. "Just-" Her lips brush his mouth as she speaks and the electricity crackles where she can taste his breath. "Make me feel something."

Castle surges upwards, taking her mouth and fisting one hand in her hair, sending the sparks of electricity bursting.

She stops trying to control the quivering need in her hips, allows them to resume their sensuous dance against his that he finally begins to participate in, lifting to meet the rock of her body with his own as his mouth devastates her. Kate moans at the slick of his tongue to the seam of her mouth, the plunge inside the moment her lips part for him, and glides one of her hands beneath his damp t-shirt, relishing in the sweat of his overheated skin scalding her palms and feeling the muscles of his abdomen ripple under her fingertips.

"We can't do this," he gasps, tearing his mouth away from hers, using the fingers ensnared in her dilapidated ponytail to stop her from chasing.

"Don't you dare-"

" _Here_ ," he clarifies, nipping at her bottom lip to emphasize that he's not trying to stop her, this. "Showers?" he asks, as if for permission, as if she isn't the one who pinned him to the floor and trapped him with her weight, with her want and her need.

Though, he could have easily overpowered her. If he had wanted to.

"Yes," she breathes, nodding eagerly and prepared to stagger to her feet, drag him to the adjoining room of showers, but Castle curves his large hand at her ass, securing her body firmly against his as he rises to his feet.

Kate locks her arms around his neck, her legs around his waist, and scrapes her teeth to his jaw while he strides to the locker room. They end up against the wall beside the sinks first, her back to the cold tile as Castle pins her hands above her head with only one of his.

"Fuck, _yes_ , just like that," she hisses, dropping her head back against the wall as he sucks hard on her pulse, undulating his lower body rough but perfectly into hers, imitation of what she could have if he was naked already. "Clothes - get them off."

Castle's hands snag in her tank top first, stripping her of the fabric and admiring the hard lines and defined planes of her upper body, palming the mounds of her breasts through the black fabric of her sports bra.

She stabs her bottom lip with her teeth to bite back the whine lodged in her throat and instead focuses on using her newly freed hands to jerk and tug his shirt upwards, working at his pants the second he reaches for the hem of the shirt himself.

By no means will they be going slow, but Kate does spare a moment to appreciate the muscles of his chest, his arms, his back, all taut and rigid beneath her wandering hands, contracting at the touch of her fingers. He radiates strength and security, and she hates it, hates that she loves it, but he makes her feel safe, protected.

Her abdominals jump at the graze of his fingertips on an exploration of their own and her back arches harshly when he slips them beneath the damp edge of her sports bra, peeling the exercise gear from her skin, over her head to drop it into the growing pile at their feet.

"Rick," she breathes his first name for a change, knotting her fingers in his hair as his mouth dusts along the slope of her breast, the heat of his breath coating her nipple before his lips close around the taut peak, his tongue adding gasoline to the fire already consuming her system.

Goosebumps erupt along her flesh as he travels across her chest with his mouth, showing her opposite breast the same attention while simultaneously pulling her from the wall. Her body curls around him, around the work of his mouth, clinging as he maneuvers his way into the nearest shower stall.

"Pants," she croaks, snagging the fabric of his workout pants in her toes and tugging hard enough to drag the elastic waistband past one hipbone.

Castle helps her feet find the tile floor, holding to her outer things through the descent of her legs from around his waist. She wobbles for a second, but he doesn't smirk, too busy hooking his thumbs in the waistband of her bottoms and sliding them down the long lines of her legs, pausing between them.

Her shoulder smacks into the cold water nozzle when he places his mouth on her, gliding his tongue through the soaking slit of her folds.

"Cas-tle," she pants, her knees growing embarrassingly weak, trembling at the nudge of his nose to her clit. "Want you. Now."

Rick makes one last swipe through the wetness between her legs, devotes a moment to suckle at the swollen bud of her clit and pull that whine she had been withholding from her throat.

She breathes a sigh of relief when he steps back to remove the last of his own clothing, kicking both pairs of pants from the shower stall and reaching for the shower nozzles without looking, his eyes piercing and solely on her. The water comes spilling through the shower head, sharp and cold, but barely noticeable when she has Richard Castle pressing her into the slick tile wall, clearing her head with his tongue in her mouth better than any cold shower ever could.

"Lift me up again," she demands, her body already slipping and sliding against his, the friction delicious but lacking the leverage she wants.

Castle huffs, but complies. Partially.

"You're bossy," he comments, hoisting one of her legs up to curl at his hip, but not the other.

Kate blinks through the warming spray of water to raise an eyebrow in challenge, but the tip of his cock is slicking through her folds, teasing at her entrance, making her writhe and buck forward for him.

He doesn't torture her any longer, pushing inside in one smooth thrust and smothering the moan she can't control with the seal of his mouth to her lips. Beckett coils her arms around his neck, her nails piercing the skin stretched across his trapezius muscle, and hums into his mouth in appreciation when he hauls her other leg up to twine around his waist, deepening the angle.

Her training officer has slammed into her, tangled limbs with her, and pinned her down with his body multiple times before, but never like this, never this good.

"Harder," she begs, not even ashamed of the need in her voice. Because she needs this, needs him and this glorious wash of heat and overwhelming sensation that only he has been able to elicit and send coursing through her bloodstream. And something tells her that maybe he needs her too.

Castle withdraws almost completely from her, plunges back in, and the stars begin to burst in the corners of her eyes.

"Close?" he gets out against the hollow of her throat, licking at the water gathering there, and she gasps out an affirmative response, shuddering when one of the hands supporting her thighs rises to steal one of hers from his back, pressing it into the wall above their heads, filling the spaces of her fingers with his.

The starbursts burn brighter behind the lids of her eyes, exploding in blinding colors as her inner muscles seize around him, coaxing his release to coincide with hers and sending them both shattering.

She thinks if the muscles of his legs were not so well disciplined, they would go collapsing to the floor, but Castle holds their combined weight, allowing only their interlocked fingers to slip from their place against the wall, falling to rest near her hip.

Kate peels her eyes open, a great effort with the water clinging to her lashes and the final vestiges of her orgasm still swimming through her senses, and tilts her head back into the wall, gulping down air and the mist of the shower. A harsh shiver wracks her body at the absentminded touch of Castle's lips trailing along the cords of her neck, up to her chin.

Mm, it's nice, but intimate, too personal, and that isn't what they agreed upon.

Kate clears her throat and wiggles her fingers free from his, holds to his shoulders to keep from slipping. Though the wet slide of friction is so good, she wouldn't mind it again, but no. No, enough for now.

"We should-"

"Oh, yeah," Castle murmurs, gripping her waist to balance her as she unhooks her ankles and retracts her legs, biting her lip when he slips from her. "This doesn't change anything, Beckett. We-"

"It changes nothing," she repeats with a firm head nod, locking eyes with him through the spray of the shower that has done little to make her feel clean. "It's just... a bonus, to my training."

"Kate," he huffs, wiping at his eyes. "Don't put it like _that_. It makes me feel like I'm taking advantage of you or-"

"You should know by now that I never do anything that I don't want to do," Beckett states, planting both hands on his cheeks and holding his gaze. "You may be my superior here, but I'm an adult, Rick. We're two consenting adults and by no means are you taking advantage of me. Besides, no one has to know."

"No one _can_ know," he reiterates, using the broad wall of his back to shield her from the pelting rain of hot water. "I could lose my job and you could be suspended."

"Then keep it like this," she shrugs. "Just us."

"It's risky-"

"Yeah, but we'll be careful," Beckett assures him, ignoring the tiny, nagging voice in her head that sounds suspiciously like the M.E in training she recently met during their tour of the morgue a couple of weeks ago telling her this is a bad idea. "We'll go somewhere else next time. Out of the precinct."

Castle purses his lips for a moment in contemplation, but she knows she has him, doesn't have to wait long for him to confirm it.

"Your place or mine?"

"Yours," she mumbles, drifting forward to graze her knuckles over his navel, traipsing down, down, down until her fingers are curling around his hardening length, caressing until his hips jerk forward, pin her to the wall once more. "But for now, let me take advantage of you one more time."


	2. Chapter 2

Castle glances pensively to the pelting of rain against his apartment window, the flicker of lightning and accompanying rumble of thunder. Storms were once calming for him, a nice soundtrack to write to, but that had been years ago. He hadn't touched his moleskin notebook, opened a word document, since his world had been turned upside down. Rarely does he even think of his short-lived writing career anymore, not when his work at the Twelfth precinct has consumed every ounce of his time and energy for the last decade.

Well, that is, until he had met his latest trainee. She did a fair job of stealing his free time, his attention, and even made his mind swirl with ideas, fingers twitching with inspiration that was always overpowered, swept clean from his head by the heat of her mouth and the seal of her skin over his.

Kate had told him she was coming over earlier, teasing him with dirty promises and heated glances all day, but they had parted ways in the precinct for the day nearly four hours ago and he has yet to hear from her again. She had told him when this entire mess had begun over a month ago that she wasn't looking for a boyfriend, but that didn't stop him from worrying like one.

Castle's concern evaporates before the fifth hour of radio silence can approach, the knock on his apartment door cutting through his thoughts of worst case scenarios, and he works to keep a normal stride on his way to the front door.

The storm raging outside has drenched her, but he can still distinguish the tears staining her cheeks from the raindrops on her skin.

"What happened?" he questions, drawing her inside with a hand on her shoulder and taking the sopping weight of her leather jacket from her arms. No uniform, jeans and a tasteful button up blouse now soaked through, which tells him she went somewhere after work. He had assumed as much, but obviously, wherever she had gone had caused her grief. "Talk to me, Beckett."

"I don't want to talk," she rasps, turning to him once her arms are free from the confines of her jacket and placing her hands to his chest, shoving him back into the door, effectively slamming it closed.

"Kate-"

"I'm here because I need to _not_ talk," she growls, pressing forward and trapping his thigh between both of hers, sinking down and moaning at the friction, the noise so desperate and sorrowful. "Don't make me talk, Rick."

Oh, he'll make her talk. He always does. But he'll wait, wait until the tension has drained from her body and she's left soft and pliable against him. He'll give her what she wants, like always, and demand the same from her later on. They've always been good at compromise since they began sharing bodies and beds.

Castle bands his arms around her, hauls her up higher on his thigh and flexes the muscles beneath her, glides his hands underneath her soaked top, around to the front of her jeans, while she rocks against him.

He kisses her when she tilts her chin up, her mouth open and wanting, and he thinks that's one of the most beautiful things about this intricate arrangement they're entangled in - how closed off she is for everyone else, everywhere else, but how open she is for him.

Her moan spills into his mouth when his fingers slip beneath the waistband of her panties, dipping into the scalding wet heat of her, his thumb massaging her clit while his fingers ease into her. Kate muffles her sob against his neck, her arms coming around him like a vice, and he speeds up the thrust and curl of his fingers, working her to her orgasm hard and fast, playing her body with well-practiced skill.

She falls apart in his arms, slumping forward against his chest, and panting harshly as she floats back down from the crest of her pleasure. But her mouth is open at his neck moments later, her tongue laving at the sensitive spot beneath his jaw that she's memorized, and he can't help drawing her in tighter against him.

"What happened?" he repeats, earning a growl of frustration he knows well against his jawline, an irritated nip of her teeth.

"Why does it matter?"

"Because something happened," Castle murmurs, lifting a hand to her cheek to brush his thumb along the path of her dried tears.

"No," she sighs, relenting with her head to his shoulder. "Nothing happened, I just - I went to visit my dad. It was a mistake."

Shit. He knew about Jim Beckett, had met the man actually, when they'd had to arrest him for public intoxication a little less than a month ago. It was the first and only time she had sought him out after work without warning, showing up at his doorstep with desperation bleeding through her eyes, spilling down her face with the tears that split his heart in half. Kate Beckett did not cry.

It was the first time he had taken his time with her, carrying her to his bed and laying her down with care, tending to her body with the request that had fallen from her lips the second he had opened the door echoing in his mind.

 _Make me feel something. Something good, Castle._

He had given her everything, held her as she fell asleep, and woke only a few hours to find the other side of his bed empty and cold.

"Worse?"

Kate nods, knotting her fingers in his shirt. "Today's her birthday."

"Kate," he whispers in horror, but her head shakes vigorously against him.

"No, don't - don't. I don't want to think about it. I've done such a good job of not thinking about it, of not falling apart today, Castle. Please-"

He hoists her up into his arms, but instead of walking her to his bedroom and laying her out across his mattress, he holds here there in the foyer of his modest apartment, cradles her there, and kisses the corner of her eye. She begins to cry again, silent tears that trek down her cheeks and onto his throat, but she doesn't make him put her down.

* * *

"It was my daughter."

Kate's eyes flutter open in the moonlit darkness to meet his, question and a flicker of concern filling her gaze as she rolls towards him in the bed. He had carried her to his bedroom after the slow seconds of vulnerability had slipped by and her tears had dried on his neck. They'd fallen asleep not long after he had pushed inside her, moved ardent and unhurried within her until they were both desperate and breathless.

"You had a daughter?" she inquires softly, the sheet slipping from her torso to pool at her waist.

"For a little while," Castle whispers, directing his gaze to the ceiling to cease from looking at her, from seeing the care she pretends not to possess. She'll be a good cop, comforting families of victims; most lack the necessary empathy, but she overflows with it because she knows just as well as he does what it's like to lose the one you love most.

"She was with my ex-wife for the weekend," he continues at the offer of her silence. "Meredith wasn't a bad mother, but Alexis had never been a priority for her. They were on a plane to Paris because Meredith insisted they should go there for lunch. Alexis was still young, scared of flying, but she wanted to please her mom..." He sighs, hates the thought of his baby girl so scared and alone, still hates it enough that his entire chest clenches like a fist at the memory of it. "They were almost there, but before they could land, there was an altercation with Meredith and a flight attendant. There was a gun. It went off."

"Castle," she breathes, the whisper of his name doused in sorrow. She already knew how his story ended and he was glad, thankful he didn't have to finish it.

"That's why I became a cop." He shrugs, his shoulders shoving into his pillow, rattling his bruised heart against the cage of his ribs. "I knew your story. I thought it was only fair you knew mine."

"You didn't have to tell me," she murmurs, her body inching closer to his, the heat of her skin warming his side.

After spending all of this time with her, he knows for a fact that Kate Beckett does not comfort with touch. Not anyone but him, apparently. With him, she curls in close, encompasses him in her warmth, her compassion, and he is reminded how lucky he is to be allowed a piece of this woman's broken heart.

Castle returns her embrace, smearing a kiss to her temple and stroking the pointed wing of a shoulder blade. "I wanted to."

Beckett steals the hand from her shoulder, knots their fingers and rests the tangled digits atop his chest.

"Good." She snuggles - something he never thought she would be approving of - into his side, the curves and planes of her body sinking into his, covering him in reassurances he never knew he wanted from her. "I want you to tell me things."

"You do?" he murmurs, tentatively raising his hand to her head, combing his fingers through the snarls of her still drying hair. Cuddling in bed, twining limbs and caressing her scalp with his fingers, has always been too intimate for them, too personal for two people who work together during the day and fuck by night, but she doesn't swat his hand away, doesn't shift to the opposite end of the mattress for her clothes or ask him to do the same.

She lies with him sated and content and oh... oh, this is bad. This is making him want things, things with her that he has no business wishing for.

Especially not with his trainee.

"Yeah, Castle," she sighs, already drifting, her breath skittering out against his throat.

She has never slept over before, neither has he when they've done this at her place, but like hell will he ever tell her to go. Not when he wants more than anything for her to stay.


	3. Chapter 3

Kate follows him into the empty conference room, her head down and her heart in her throat and her eyes burning so badly she has to blink every other second to keep the sting of salt under control.

Castle holds the door for her, but she is the one to press her back to the frame once it is closed, crossing her arms tightly over her chest to force the stupid muscle in her chest from falling apart. Mere hours ago they had woken together in her bed, showered in her bathroom, balanced against the window to keep from collapsing over the edge of the claw foot tub as they had made use of the extra time beneath the heated spray. He had left first, as always, smeared a kiss to her mouth on the way out of her front door, but standing here now with his words echoing in her head... mornings in her wrinkled sheets and sex in her shower seem like another lifetime.

"What do you mean you're leaving?" she whispers the words that greeted her upon arrival at the Twelfth half an hour ago.

Three months. Three months of his touch and his taste and the guidance he has provided her with as a superior officer. Three months of feeling something other than remorse, of feeling something good, beautiful, and right for the first time in too long. And now he's taking it all away?

"Montgomery knows."

Her head tips back against the door, her vision blurred but trained on the ceiling. "How?"

"Someone must have seen something, reported it, I don't know - I... he called me into his office this morning, told me he would process the suspension as quietly as possible-"

"No," she rasps, pushing off of the door to meet him in the middle of the room, coiling her fingers around his biceps. "Not because of me, don't-"

"Shh, this isn't your fault." The contradicting mixture of heartbreak and resignation staining his eyes scares her, has the cage of her ribs collapsing in on her lungs, her heart, shutting her down from the inside out. She is _not_ needy, far from dependent, never has been, but fuck if she doesn't need him in her life, in her bed and in her heart.

He can't abandon her too.

"It's mine," Castle continues, cupping her shoulders in his palms, smoothing his thumbs over the starched material of her uniform. "You're a rookie, Kate. And I was supposed to be helping you and instead I-"

"Shut up," she hisses, digging her nails into his arms. "Don't you dare treat me like some mistake, like some vulnerable little girl-"

"I never called you a mistake," her argues, just as fierce, that terrifying look of resign giving way to the passion she knows so well. "It wasn't a mistake, we could never... but I know how much this job means to you, how much you need it and how hard you work for it. I put that in jeopardy."

"And I didn't do the same?" she challenges, because yes, this job may mean the world to her, may have been her lifeline in the beginning of all this, but his holds the same value. Castle's eyes flicker down and she sees her chance to get through to him, to show him the truth. "Being a cop is important to me, solving my mom's case... it's been the single thing to drive me since she was murdered, Rick."

He nods, his hands dropping from her shoulders, but she snags them on their descent to his sides, draws them in until his knuckles press hard against her abdomen.

"But you're important too," Kate breathes, thumbs sweeping back and forth over the veins running like rivers atop his hands. "And I've - I can't give this up. Not when you're the only good thing I have left."

Her training officer is being suspended because of her, but that doesn't stop him from lifting his hands to her face, cradling her cheeks in his palms as he kisses her, hard and affirming, just what she needs.

When she met him, she was drowning, and that hasn't changed, but having him... it's like having a life preserver amidst the sea.

"We'll figure it out," he promises her, swearing the words into the seal of her lips. "I don't know how, but I'm not going anywhere. You're stuck with me, Beckett."

The wall of panic in her chest dissipates, dissolving and leaking out of her as the sigh of relief rushes from her mouth into his. She is under no delusions that this will be easy, but she is beginning to believe that the hardest things in life are the things most worth doing. And she likes to believe her mother would be proud of that.

* * *

Kate strips the padded, fingerless gloves from her hands as she walks down the hallway, flexes her fingers to alleviate the tension lacing along the thin bones, and bends to retrieve her key from the inside of her shoe. She had finished the last of her paperwork only a few minutes past five, had clocked out shortly after, but had been craving a workout, to feel the burn in her muscles and the sweat dripping down the taut planes of her skin. The week had been busy, four homicides, digging through dumpsters every morning with Esposito and their newest addition to the homicide department, Ryan, and Beckett had hardly been allowed the opportunity to squeeze in a good workout.

Her body was thoroughly decompressed now, aching after an hour of sparring with the precinct's punching bag and deciding to run the two miles home with her bag slung over her shoulder. She'd have to ask Rick to work out the kinks in her muscles later tonight.

Beckett's lips curl, grinning like an idiot in his hallway. He knew the job, knew the physical toll it took, and he was _always_ more than willing to use those talented hands to soothe every inch of her, to work out every knot of tension, replacing it with an entirely new, far more welcome kind more often than not.

Kate swipes a sweaty strand of hair back from her forehead and lifts her key to his door, but before she can insert it into the lock, the door is flying open, and Richard Castle is sweeping her into his arms, spinning her around in the middle of his doorway.

"Rick," she huffs out on a laugh, still trying to catch her breath, clutching his shoulders with her aching fingers, dropping her gloves and the light messenger bag midway through the twirling. "What's going on?"

Castle puts her down, catching his own breath, and she wants to tease him about being an old man, but his eyes are shining so brilliant and blue, his smile so wide, and oh... oh, she hopes-

"They're going to publish it," he whispers, confirming it, and she thinks the smile that claims her lips may even rival his. "Gina said it's good and that Black Pawn loves it so much, they're already considering offering me a three book deal."

"Castle," she breathes, her fingers rising to press to her lips, trying to contain the untamable and ever widening stretch of her mouth, but she's just so proud of him. So proud, she can't help lifting on the toes of her sneakers to smear her smile to his.

Rick hums in approval, his arms slithering around her body, hands sliding beneath her drenched t-shirt to coast up and down her sweat slicked skin.

"Stop," she chuckles, nipping at that upturned bottom lip. "I'm all sweaty and gross."

"Hot," he mumbles, tracing the material of the sports bra clinging to her back. "Both literally and figuratively."

Kate rolls her eyes, steals one last kiss from his mouth. "I'm so proud of you, Rick," she murmurs, withdrawing from his lips to caress his cheek with her hands, brushing her thumbs along the crinkling lines at the corners of his eyes, the evidence of his happiness.

His cheeks heat beneath her palms, his grin turning bashful, and she laughs softly at him for it. He had been so nervous to start writing again, especially after she had learned of his reason for giving up on the passion in the first place, but after resigning from his work at the Twelfth, he had taken it up again, claiming that it would remain nothing more than a hobby to occupy his time until he found a new line of work to pursue.

That had been a year ago.

"I'm proud of you too, Detective Beckett. Grateful as well."

"Not a detective yet," she hushes him, but the pride in his eyes doesn't dim. Never. He's always so proud of her. Grateful to her for 'inspiring' him and being the muse for his newest protagonist, Nikki Heat.

She still hates the name.

"I know, but you will be. Montgomery told me you'll likely receive the promotion by the end of the year, remember?" Rick quips, drawing her through the door with his hands on her hips and using her body to close it the rest of the way until the lock clicks and she's dropping her key onto the end table near the entry. She hasn't moved in with him, not yet, but his apartment has certainly become more of a home than hers. Then again, as long as he's with her, she doesn't care too much about where she spends her time. "And after watching you work so hard, I cannot wait to see you wearing that badge. Though, I will miss the uniform."

"Who says it has to go anywhere?" she hums, quirking her brow and bumping her hips into his, watching the vibrant blues of his eyes darken and feeling the pleasant and oh so welcome burn ignite in her stomach.

"We should celebrate," he decides, his thumbs hooking in the hem of her shirt, grazing along the skin of her lower abdomen. "But first, we should shower."

"Mm, good plan." Her arms slip around his neck and Castle hoists her up without question, the dance between them so effortless, so well-rehearsed after a year and a half, but still so deliciously good. Still so good for her. "Come spar with me next week," she adds while Rick walks her through the living room, into his bedroom and the adjoining bathroom tucked inside.

His brow arches at her, a smirk flirting with his lips that she leans forward to tease apart with her tongue. "Want a partner who can actually pin you to the mat?"

"Maybe." Beckett rocks her hips, pulls a groan from his chest with her teeth. "You know a guy?"

"I better be the only guy," Castle growls and places her on the sink, tugs the dampened t-shirt over her head and tosses it to the ground. "I can still take you."

"We'll see," she muses, her spine arching forward at the slide of his hands beneath her sports bra, easing it over her head and gliding his fingers over her naked flesh. "No," she adds on a gasp. "Don't have to take me. Already have me."

"Mm, Beckett," he chuckles against her jaw, kissing a path to her ear. "Getting soft on me?"

"Shut up," she mutters, twining her legs around his waist and holding him close for a second, nuzzling his neck and sighing contently at the skate of his palms along her back, arousing but soothing all at once. She hates him for evoking the sentimental parts of her, for reminding her of how they met, how he changed everything. "Still hate you."

The laugh rumbles through his chest, has her lips curling against his throat.

"Love you too, Kate."

She hates how those words still knock the breath out of her too.

"Love you back," she sighs out, pulling back to seal another kiss to his mouth and rocking her hips. "Now remind me how much."


End file.
